Conventionally, a needle made of stainless steel has been generally used as a sewing needle for medical use. In recent years, for the purpose of lightening a patient's load, a need for a thinner medical needle has been increased and demanded. However, when the needle is made to be thinner, deflection and bending of the needles are liable to occur, so that there has been posed a problem such that an operability of the needle is disadvantageously lowered in a short time period.
In order to prevent the above problem, a raw material having higher strength and rigidity than those of the stainless steel has been demanded. Particularly, a rhenium tungsten alloy (Re—W alloy) is a material having high strength and rigidity due to a solution-strengthening function of tungsten into rhenium. Concretely, in a case where a wire diameter D (mm) is within a range of 0.10 to 0.40 mm and a tensile strength of the rhenium tungsten alloy wire is expressed to be T (N/mm2), a maximum value of T (N/mm2) was within a range indicated by an equation (3) hereunder, which is expressed as a function of the wire diameter D (mm).T<6314.6×D2−7869.3×D+4516.3  (3)
On the other hand, for example, Japanese Patent Laid-Open (Unexamined) No. 7-204207 (Patent Literature 1) discloses a medical needle for surgical use. The medical needle is made of tungsten alloy containing rhenium (Re) at an amount of 30 mass % or less. The Patent Literature 1 reported that medical needle for surgical use, having high tensile elastic modulus and high yield strength in tension, can be obtained.